The primary objective is to prevent the spread of AIDS by assisting intravenous drug users to access appropriate treatment earlier, by encouraging these persons to remain in treatment, to attain treatment plan goals, and to follow after-care plans. Case managers will be assigned to facilitate the above. The specific aim of this research project is to alter a segment of the treatment provided by the substance abuse treatment system. Specifically, the aim is the reduction of needle sharing among intravenous drug abusers. An experimental group of 150 will be randomly selected upon assessment and will be assigned case managers. A control group of 150 will be selected that matches the experimental group on sex and race. This group will not be assigned a case manager but will receive treatment as usual. The case managers will be involved in assessment, planning, linking, monitoring, and client advocacy. Each group will be tracked for a 3 year period to determine if the presence and advocacy of a case manager has a positive impact in reaching the stated objective. A series of questionnaires and other assessment tools will be administered. Case managers will refer to/purchase services that are most appropriate for the needs of the individual clients.